CC3220SF-LAUNCHXL: Gratuitous ARP using the SimpleLink stack.

Glenn Kosteva1

Hi,

The WiFi chip on our sensor is running code similar to the network_terminal example.
It is currently running the latest stack version: simplelink_cc32xx_sdk_3_40_00_05.

In the our wireless routers, we have found that the TI WiFi chip is not showing up in its -ARP list. (All other devices do.)
We are wondering, does the SimpleLink stack do a gratuitous ARP after obtaining an IP address?

If not, is there a way that we can command the WiFi chip to do an ARP?

Thanks, Glenn.

over 5 years ago

0 Michael Reymond over 5 years ago

TI__Mastermind 40965 points

Hi Glenn,

Have you tried performing some network activity that would trigger an ARP on the CC3220? As part of your code, you'll probably be connecting to a remote server and as part of that connection the CC3220 will perform an ARP automatically. This ARP should populate your AP's ARP list.

That being said, there is a method to trigger a manual ARP request. You can open a raw socket, build the ARP request, and then send out this ARP request. I detail this procedure in my post here:

https://e2e.ti.com/support/wireless-connectivity/wifi/f/968/p/845693/3134002#3134002

Let me know if you need more clarification or have further questions on performing that ARP.

Regards,

Michael

0 Glenn Kosteva1 over 5 years ago in reply to Michael Reymond

Intellectual 605 points

Hi Michael,

I tried using the code you referenced, my version attached below.
I verified my IP and my gateway and I can ping my address and see that on the Wireshark capture.
I don't see any ARPs from this send.

Do you see anything wrong in my function?

Thanks, Glenn.

int WiFi_Send_Arp(void)
{
int len, lstatus;
char buf[100];

struct arp_hdr* arp1;
struct arp_ethip* ethip;
struct arp_eth_hdr* ethhdr1;
unsigned char dest_mac[6] = {0XFF, 0XFF, 0XFF, 0XFF, 0XFF, 0XFF};
unsigned char eth_type[2] = {0x08, 0x06};

//Check for network connection
if ( !(app_CB.CON_CB.IpAddr) && !(app_CB.CON_CB.GatewayIP) )
return -3;

//setup the packet
ethhdr1 = (struct arp_eth_hdr*)buf;
memcpy(ethhdr1->dst_mac, dest_mac, ETH_ADDR_LEN);
memcpy(ethhdr1->src_mac, myMacAddress, ETH_ADDR_LEN);
memcpy(ethhdr1->type, eth_type, 2);

arp1 = (struct arp_hdr*)(buf+ ETH_HDR_LEN);
arp1->ar_hrd = sl_Htons(ARP_HRD_ETH);
arp1->ar_pro = sl_Htons(ARP_PRO_IP);
arp1->ar_hln = ETH_ADDR_LEN;
arp1->ar_pln = IP_ADDR_LEN;
arp1->ar_op = sl_Htons(ARP_HRD_ETH);

ethip = (struct arp_ethip*)(buf + ARP_HDR_LEN + ETH_HDR_LEN);
memcpy(ethip->ar_sha, myMacAddress, ETH_ADDR_LEN);
memcpy(ethip->ar_spa, (void *)app_CB.CON_CB.IpAddr, IP_ADDR_LEN); //src IP
memcpy(ethip->ar_tha, dest_mac, ETH_ADDR_LEN);
memcpy(ethip->ar_tpa, (void *)app_CB.CON_CB.GatewayIP, IP_ADDR_LEN); //dst IP

len = ARP_HDR_LEN + ARP_ETHIP_LEN + ETH_HDR_LEN;

//send the packet
lstatus = sl_Send(app_CB.socket, buf, len, 0);
return (lstatus);
}

0 Glenn Kosteva1 over 5 years ago in reply to Glenn Kosteva1

Intellectual 605 points

you can close this. I.m working now.

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CC3220SF-LAUNCHXL: Gratuitous ARP using the SimpleLink stack.